Tiny Fish Climb 50-Foot Waterfall in Congo Basin

For over 50 years, people in Central Africa whispered stories about tiny fish climbing waterfalls, but nobody could prove it. Now, researchers have documented shellears making an incredible 10-hour vertical journey up Luvilombo Falls in the Congo Basin, becoming the first confirmed rock-climbing fish in Africa.

The shellears, scientifically known as Parakneria thysi, use hook-like structures on their fins to grip wet rock faces. They wiggle their tails for momentum, essentially swimming straight up a 50-foot waterfall.

The journey is grueling. These fish climb in bursts, then rest anywhere from 15 seconds to over an hour before continuing. Many fall and have to start over from the bottom.

Only the smallest fish succeed. Shellears under two inches long can make the climb, but larger ones become too heavy to haul themselves upward. The entire trek takes about 10 hours for the lucky ones who complete it.

Ichthyologist Pacifique Kiwele Mutambala from the University of Lubumbashi in the Democratic Republic of the Congo spent years documenting this behavior. His team observed thousands of fish during peak migration in mid-April, following major floods at the end of rainy season.

The discovery almost didn't happen. Co-author Auguste Chocha Manda filmed the climbing fish 17 years ago but lost the footage. The team returned in 2018 and 2020 to capture the proof the world needed to see.

Scientists have spotted rock-climbing fish in South America, Asia, and Australia, but never before in Africa. Researchers still don't know exactly why these fish risk everything to climb, though they suspect the fish are escaping predators, seeking food, or looking for mates upstream.

Why This Inspires

This discovery shows that nature still holds secrets waiting to be revealed, even behaviors people have talked about for generations. The documentation arrived at a critical time: migratory freshwater fish worldwide have declined by 81 percent since the 1970s due to dams, habitat loss, and overfishing.

Understanding the shellears' migration route helps protect them. During dry season, people sometimes divert Luvilombo Falls for crop irrigation, cutting off the fish's path. The fish also gather in large groups at the waterfall's base, making them vulnerable to illegal net fishing.

The Congo Basin remains one of the least-studied ecosystems on Earth, and this fish's remarkable ability reminds us why protecting these waterways matters. "It illustrates that there are wonders out there that surpass our imagination," Kiwele Mutambala told reporters.

Now the world knows these tiny climbers are real, and that knowledge might just save them.